Preadapted to adapt: underpinnings of adaptive plasticity revealed by the downy brome genome

Natural variation of CsUGT71A60 determines growth and cold tolerance via regulating cytokinin glycosylation in Camellia sinensis

Cold stress severely limits tea plant (Camellia sinensis) productivity, yet the molecular mechanisms underlying cold adaptation remain elusive. Here, we identified a cold-inducible glycosyltransferase, CsUGT71A60, through integrative genome-wide association studies (GWAS) and proteomic profiling. Natural variation in CsUGT71A60 was strongly associated with cold tolerance, as evidenced by linkage disequilibrium analysis of flanking SNPs. Functional characterization revealed that CsUGT71A60 specifically catalyses the glycosylation of cis-zeatin to form cis-zeatin 9-O-glucoside in vitro and in vivo. Overexpression of CsUGT71A60 in Arabidopsis enhanced cold tolerance and agronomic traits, including germination rate, tiller number and seed weight, while delaying flowering. Transient silencing of CsUGT71A60 in tea plants disrupted cis-zeatin homoeostasis, impairing antioxidant defences and osmotic regulation under cold stress. Mechanistically, the transcription factor ARR (TEA021099) directly binds to CRM elements in the CsUGT71A60 promoter, activating its expression to fine-tune cytokinin signalling. This study unveils a dual-function glycosyltransferase that orchestrates stress tolerance and developmental plasticity, offering a strategic target for breeding climate-tolerance crops without yield penalties.

Phenological sensitivity of Bromus tectorum genotypes depends on current and source environments

Plants respond to their environment with both short-term, within-generation trait plasticity, and long-term, between-generation evolutionary changes. However, the relative magnitude of plant responses to short- and long-term changes in the environment remains poorly understood. Shifts in phenological traits can serve as harbingers for responses to environmental change, and both a plant's current and source (i.e., genotype origin) environment can affect plant phenology via plasticity and local adaptation, respectively. To assess the role of current and source environments in explaining variation in flowering phenology of Bromus tectorum, an invasive annual grass, we conducted a replicated common garden experiment using 92 genotypes collected across western North America. Replicates of each genotype were planted in two densities (low = 100 seeds/1 m2, high = 100 seeds/0.04 m2) under two different temperature treatments (low = white gravel; high = black gravel; 2.1°C average difference) in a factorial design, replicated across four common garden locations in Idaho and Wyoming, USA. We tested for the effect of current environment (i.e., density treatment, temperature treatment, and common garden location), source environment (i.e., genotype source climate), and their interaction on each plant's flowering phenology. Flowering timing was strongly influenced by a plant's current environment, with plants that experienced warmer current climates and higher densities flowering earlier than those that experienced cooler current climates and lower densities. Genotypes from hot and dry source climates flowered consistently earlier than those from cool and wet source climates, even after accounting for genotype relatedness, suggesting that this genetically based climate cline is a product of natural selection. We found minimal evidence of interactions between current and source environments or genotype-by-environment interactions. Phenology was more sensitive to variation in the current climate than to variation in source climate. These results indicate that cheatgrass phenology reflects high levels of plasticity as well as rapid local adaptation. Both processes likely contribute to its current success as a biological invader and its capacity to respond to future environmental change.

Local adaptation to climate facilitates a global invasion

Local adaptation may facilitate range expansion during invasions, but the mechanisms promoting destructive invasions remain unclear. Cheatgrass (Bromus tectorum), native to Eurasia and Africa, has invaded globally, with particularly severe impacts in western North America. We sequenced 307 genotypes and conducted controlled experiments. We found that diverse lineages invaded North America, where long-distance gene flow is common. Ancestry and phenotypic clines in the native range predicted those in the invaded range, indicating pre-adapted genotypes colonized different regions. Common gardens showed directional selection on flowering time that reversed between warm and cold sites, potentially maintaining clines. In the Great Basin, genomic predictions of strong local adaptation identified sites where cheatgrass is most dominant. Preventing new introductions that may fuel adaptation is critical for managing ongoing invasions.

Current status of community resources and priorities for weed genomics research

Weeds are attractive models for basic and applied research due to their impacts on agricultural systems and capacity to swiftly adapt in response to anthropogenic selection pressures. Currently, a lack of genomic information precludes research to elucidate the genetic basis of rapid adaptation for important traits like herbicide resistance and stress tolerance and the effect of evolutionary mechanisms on wild populations. The International Weed Genomics Consortium is a collaborative group of scientists focused on developing genomic resources to impact research into sustainable, effective weed control methods and to provide insights about stress tolerance and adaptation to assist crop breeding.

Weed biology and management in the multi-omics era: Progress and perspectives

Weeds pose a significant threat to crop production, resulting in substantial yield reduction. In addition, they possess robust weedy traits that enable them to survive in extreme environments and evade human control. In recent years, the application of multi-omics biotechnologies has helped to reveal the molecular mechanisms underlying these weedy traits. In this review, we systematically describe diverse applications of multi-omics platforms for characterizing key aspects of weed biology, including the origins of weed species, weed classification, and the underlying genetic and molecular bases of important weedy traits such as crop-weed interactions, adaptability to different environments, photoperiodic flowering responses, and herbicide resistance. In addition, we discuss limitations to the application of multi-omics techniques in weed science, particularly compared with their extensive use in model plants and crops. In this regard, we provide a forward-looking perspective on the future application of multi-omics technologies to weed science research. These powerful tools hold great promise for comprehensively and efficiently unraveling the intricate molecular genetic mechanisms that underlie weedy traits. The resulting advances will facilitate the development of sustainable and highly effective weed management strategies, promoting greener practices in agriculture.